For many types of footwear, a manufacturer creates an upper by cutting one or more sheet material elements from a larger panel of that same material. The manufacturer may, depending on the shoe design, join together multiple cut elements to create an upper shell. This shell can then undergo further fabrication operations and ultimately be joined to a sole structure.
Cutting upper elements from larger sheets of material creates scrap. After cutting elements from a stock material sheet, for example, the remaining parts of that sheet may be too small for use in other aspects of the upper fabrication process. Reducing scrap is often an important factor when planning production. For example, a manufacturer may cut elements from a larger sheet by arranging cutting dies so as to maximize the number of elements obtained from that sheet. In some cases, the design for a shoe upper may be affected by the amount of scrap likely to be generated. For example, a designer might desire a particular shape for an upper element so as to achieve a particular aesthetic or to achieve some other goal. However, it may be difficult to cut that shape from commercially available sheets of a particular material without leaving large amounts of unusable scrap. As a result, the designer may be forced to change the shape of the upper element so that more of the commercially available sheet can be utilized.
Even in moderately sized production runs, a large volume of scrap might be generated. Such scrap often enters the waste stream and is frequently burned. Recycling this scrap can be difficult. For example, some upper designs may incorporate multiple types of materials. Not all of those materials may be recyclable, or one material may be recyclable for some purposes and another may only be recyclable for different purposes. Separating these different types material scraps for recycling might be labor intensive or otherwise impractical.
The above concerns are not limited to manufacturing of footwear. Many other types of goods can include manufacturing operations that generate scrap, which scrap may be difficult to recycle or otherwise dispose of in an environmentally-conscious manner. For commercial, environmental and other reasons, there remains a need for ways to reduce the amount of material scrap that enters the waste stream during production of shoes and/or other types of goods.